The present invention relates to a glass product machining apparatus used to shape the surface of a glass product having a surface, such as a panel that constitutes the front portion of a Braun tube or cathode ray tube of a television set.
After a glass product having a surface, e.g., a glass panel that constitutes the front portion of a cathode ray tube of a television set, is press-molded, its surface is polished and finished into a smooth one. Conventionally, the panel surface is polished in a manner such that a polishing slurry is poured onto it as a polisher is slid thereon to correct its shape.
FIGS. 13 and 14 show the basic concept of the conventional polishing method. In these drawings, symbol P designates a panel that has a surface. The panel P is placed on a moving table 1. After the panel P is fixed to the table 1, a polisher 3 is brought into contact with the surface of the panel P under a fixed pressure F. Then, the moving table 1 is reciprocated in an axial direction T of the panel P, and a polishing slurry Q is poured into the gap between the polisher 3 and the panel P by means of a hose 4, whereupon the surface of the panel P is polished. In doing this, the whole panel surface can be polished by gradually moving the polisher 3 in a direction (indicated by arrow S in FIG. 13) perpendicular to the moving direction T of the moving table 1. In moving the polisher 3 in the direction S, the polisher 3 is inclined corresponding to the curvature of the surface of the panel P.
There are three types of polishers 3 for three different stages of polishing, rough polishing, medium-roughness polishing, and finish polishing. These polishers of different types may be prepared and changed with the progress of polishing. Alternatively, a machine is used exclusively for each polisher. In either case, a polishing slurry for each polishing stage is poured into a sliding zone between the polisher 3 and the panel P as the panel surface is polished.
In the conventional polishing system arranged in this manner, however, the surface of the glass product must be polished as the polishing slurry is poured. Correcting distortion of the product surface and polishing the surface take much time, so that the operating efficiency lowers inevitably.
Accordingly, the object of the present invention is to provide a glass product machining apparatus capable of efficiently shaping the surface of a glass product in a short time.
According to the present invention, there is provided a glass product machining apparatus for machining and finishing a surface of a glass product, which comprises a rotatable grindstone, a moving table horizontally movable under the grindstone, supporting means for supporting the grindstone for up-and-down motion, and elastic load applying means for applying a fixed elastic load to the grindstone supported by the supporting means as the position of the grindstone is shifted upward. The glass product is placed on the moving table. As the glass product, along with the moving table, moves under the grindstone, the grindstone is brought into contact with the surface of the glass product with a fixed force of pressure by the elastic load applying means. In this state, the grindstone relatively moves along the surface of the glass product, thereby grinding the product surface.
According to the invention, moreover, there is provided another glass product machining apparatus, which comprises a rotatable grindstone, a moving table horizontally movable under the grindstone, supporting means for supporting the grindstone for up-and-down motion, and position control means for controlling the position of the grindstone supported by the supporting means. The glass product is placed on the moving table. As the glass product, along with the moving table, moves under the grindstone, the position control means controls the position of the grindstone that grinds the surface of the glass product.
In the glass product machining apparatus of the invention constructed in this manner, the glass product is caused to pass under the rotating grindstone, and the surface of the glass product is ground by means of the grindstone, whereupon the surface of the glass product is finished. Thus, according to the apparatus of the invention, a polishing slurry, which is essential to the conventional polishing system, is unnecessary, so that the machining time can be shortened by a large margin. Accordingly, the efficiency of operation for finishing the glass product is securely improved. Since the polishing slurry is not used, moreover, the cost of equipment, environmental conditions, etc. can be improved considerably.
Preferably, the apparatus according to the invention is provided with a dressing machine for dressing or truing the grindstone in case of loading and so on. With this arrangement, loading of the grindstone can be easily corrected by means of the dressing machine so that the grindstone can be reused.
Preferably, furthermore, the apparatus according to the invention is provided with inclination adjusting means for correspondingly inclining the grindstone or the glass product when the surface of the glass product on the moving table is inclined at an angle to the longitudinal axis of the grindstone in the width direction of the glass product, thereby adjusting the inclination of the grindstone or the glass product so that the grindstone is in contact with the product surface throughout its length. If the surface of the glass product on the moving table is inclined with respect to the longitudinal axis of the grindstone in the width direction thereof, with this arrangement, the inclination adjusting means can bring the grindstone into contact with the product surface throughout its length despite the inclination, so that the product surface can be ground uniformly.
In the glass product machining apparatus according to the invention, the axial length of the grindstone may be substantially equal to the width of the glass product, so that the whole surface of the glass product can be ground at a stroke when the glass product passes once under the grindstone. Alternatively, in the apparatus of the invention, the axial length of the grindstone may be shorter than the width of the glass product, so that the grindstone is moved in the width direction of the glass product with each of times the glass product is caused to pass under the grindstone as the whole surface of the glass product is ground.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.